The operation of certain types of equipment can be negatively affected by the presence of environmental hazards, such as airborne contaminants and/or electromagnetic fields. To prevent this harm from occurring, some sensitive equipment may be housed in an enclosure that is designed to keep out or minimize such contaminants.
An example of a piece of sensitive equipment housed within a protective enclosure is a hard-disk drive (HDD). A hard-disk drive (HDD) is a non-volatile storage device which is housed in a protective enclosure and stores digitally encoded data on one or more circular platters having magnetic surfaces. When an HDD is in operation, each platter is rapidly rotated by a spindle system. Data is read from and written to a platter using a read/write head which is positioned over a specific location on a platter by an actuator.
A read/write head uses a magnetic field to read data from and write data to the surface of the platter. As a magnetic dipole field decreases rapidly with distance from a magnetic pole, the space between a read/write head and the surface of a platter must be tightly controlled. To provide a uniform distance between a read/write head and the surface of a platter, an actuator relies on air generated by a self-acting air bearing surface to support the read/write heads at the proper distance away from the surface of a platter while the platter rotates. A read/write head therefore is said to “fly” over the surface of a platter. That is, the air pulled along by a spinning platter forces the head away from the surface of the platter. When a platter stops spinning, a read/write head must either “land” on the platters or be pulled away.
Electromagnetic fields can interfere with the proper operation of the hard-disk drive. The enclosure of a hard-disk drive can, in some cases, amplify external electromagnetic fields, which can be problematic. To address this problem, the enclosure of a hard-disk drive may be designed to reduce the amplification of external electromagnetic fields to protect the interior of the hard-disk drive.
The protective enclosure of a hard-disk drive is formed by joining two or more different pieces together. For example, the enclosure can be formed by joining a top cover of the hard-disk drive with a base of the hard-disk drive using one or more screws. The distance between the screws determines the resonant frequencies of the electromagnetic energy entering the hard-disk drive. By shortening the distance between the screws, the resonant frequencies are increased to frequencies that did not affect the operation of the hard-disk drive. Thus, by adding more screws to the enclosure, the enclosure's ability to protect its contents from electromagnetic energy is increased. It is noted that copper tape can also be placed between screws to achieve the same affect, as copper tape acts like adding an extra screw to the enclosure. Unfortunately, adding screws and/or copper tape to the enclosure adds to the cost of manufacturing the hard-disk drive.